Category Zoology

                   Although dinosaur remains are few, we know or can deduce quite a lot from their fossilized skeletons. For example, we can calculate a dinosaur’s weight by studying its bones. Heavy animals have massive bones to support their weight, while swift-moving hunters usually have very light, hollow bones. Muscles are firmly attached to bones, and although no trace of the muscles remains in fossils, the attachment points can be seen on the bones. These tell scientists how big the muscles must have been.

                 We know that a bulky digestive system is necessary to digest vegetable matter. The herbivores would have had massive barrel-shaped bodies, while carnivores would be slimmer. The shape of the teeth tells us what type of food the dinosaur ate.

            Dinosaurs were reptiles that evolved into the most varied kinds of any living creature. They ranged from tiny bird-like animals to monstrous beasts that were the largest animals ever to live on land. The dinosaurs survived for about 150 million years. They were not all the meat-eating killers familiar from films and books; neither were most of them gigantic creatures. In fact, most dinosaurs were peaceful, browsing animals about the size of modern farm livestock.

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                       One of the most remarkable looking reptiles that ever lived was called Tanystropheus. It was about 3 m long, but almost 2 m of this length was its neck! Tanystropheus was quite lightly built, and its neck was probably not very flexible because it contained only a few vertebrae. No one is quite sure just how this creature lived or why its neck was so incredibly long, but the shape of its teeth suggests that it might have been a fish eater. Its long neck could have been extended like a fishing rod to help it catch its fish prey.

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                      Archosaurs were a whole group of reptiles that appeared during the Triassic Period. Most of them were predators, and they gave rise to animals such as the dinosaurs, the crocodiles and their relatives, and the flying pterosaurs. The archosaurs were the group of animals in which the modification to the hips and legs developed. This modification led to the dinosaurs being able to support their own weight and to stand upright. Because they were able to move more efficiently and most were fierce predators, it is thought that they may have killed off the mammal-like reptiles and other early relatives.

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                   As the reptiles multiplied they became more diverse. Among them were mammal-like reptiles called the synapsids. One of these, Dimetrodon, had a sail-like structure on its back. The sail may have helped control body temperature. By turning the sail to face the Sun these cold-blooded reptiles could absorb heat. Dimetrodon was a large, 3 m long predator with sabre-like teeth. Other mammal-like reptiles called dicynodonts are thought to have become warm-blooded to gradually evolve into the true mammals.

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                   Unlike the amphibians, reptiles were able to exploit all the available food sources and many of them adopted a vegetarian diet. These reptiles were not dinosaurs, but many looked like the dinosaurs that would  follow.

                 Carnivorous reptiles developed with long fangs to stab and tear their prey. These animals were lightly built and fast moving in order to hunt. Other were herbivores, developing teeth capable of grinding vegetation and huge barrel-like bodies to contain the massive digestive system needed to cope with a vegetable diet.

                   Although some of these reptiles looked like the dinosaurs, scientists know from studying the structure of their hip bones and limbs that most would have been more clumsy when walking or running.

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